Two long straight wires carry the same amount of current in the directions indicated. The wires cross each other in the plane of the paper. Rank points \(A, B\) \(C,\) and \(D\) in order of decreasing field strength.

Use the right-hand rule to determine the direction of the magnetic field around each wire. If you point your right-hand thumb in the direction of the current, your fingers will curl around the wire in the direction of the magnetic field.

Examine the magnetic field contributions from each wire at points \(A, B, C,\) and \(D\). Since both wires carry currents in the same direction, their magnetic fields will either add up or cancel each other at the points.

Based on the directions of the magnetic fields from each wire at the points, determine whether they add up or cancel and rank these points in order of decreasing net field strength.

After analyzing the magnetic field contributions from each wire at each point, we can rank the points in the order of decreasing field strength as follows: - \(A\) is the closest point to both wires, and the magnetic fields from both wires will add up; therefore, it will have the highest field strength. - \(B\) and \(C\) will have a certain amount of field cancellation because of their relative position between the wires; therefore, they will have weaker field strengths compared to \(A\). However, \(B\) is closer to the wires than \(C\), so it will have a stronger field than \(C\). - \(D\) is the farthest from both wires and will experience the weakest field strength. In conclusion, the points are ranked in the order of decreasing field strength: \(A > B > C > D\).